Internal Rate of Return (IRR)

Internal rate of return (IRR) is the discount rate at which a project's net present value equals zero, representing the effective annual return the project generates on invested capital.
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By Brett Helling

How IRR Works

The internal rate of return is the discount rate that makes a project’s NPV exactly zero. It represents the effective annual return the project generates on the invested capital. If a project has an IRR of 15%, it means the project’s returns, when discounted at 15%, exactly equal its costs. Any discount rate below 15% produces a positive NPV (the project creates value). Any rate above 15% produces a negative NPV (the project destroys value).

IRR is calculated by finding the discount rate r that satisfies: 0 = Sum of (CFt / (1+r)^t) minus Initial Investment. This cannot be solved algebraically for most real projects and is calculated iteratively using spreadsheet functions (Excel’s IRR function, Google Sheets’ IRR function) or financial calculators.

Interpreting IRR Against a Hurdle Rate

The decision rule is straightforward: if the IRR exceeds the organization’s hurdle rate (typically the weighted average cost of capital or a minimum acceptable return), the project should be accepted. If the IRR falls below the hurdle rate, the project should be rejected.

Example: A company’s hurdle rate is 10%. Project A has an IRR of 18%. Project B has an IRR of 7%. Project A exceeds the hurdle rate and creates value. Project B falls below the hurdle rate and should be rejected or redesigned to improve returns.

When to Use IRR

IRR is useful for communicating project attractiveness in a single percentage that stakeholders can compare to familiar benchmarks (savings account rates, stock market returns, the organization’s cost of capital). It is widely used in capital budgeting, real estate development, and private equity for go/no go decisions on individual projects.

When NPV Is Better Than IRR

IRR has known limitations that make NPV the preferred metric for comparing competing projects. IRR assumes that interim cash flows are reinvested at the IRR itself, which is unrealistic for high IRR projects. A project with 40% IRR assumes interim returns are reinvested at 40%, which is rarely achievable.

Projects with non conventional cash flows (alternating positive and negative periods) can produce multiple IRRs, making the metric ambiguous. NPV always produces a single, unambiguous value.

When comparing mutually exclusive projects of different sizes, IRR can produce misleading rankings. A small project with 30% IRR may create less total value than a large project with 20% IRR. NPV captures the absolute dollar value; IRR only captures the rate.

Commonly Confused With

TermKey Difference
NPV NPV calculates the absolute dollar value a project creates. IRR calculates the percentage return rate. NPV is preferred for comparing projects of different sizes. IRR is useful for go/no go decisions against a hurdle rate.
ROI ROI is a simple ratio (net benefit / cost) that does not account for the time value of money. IRR accounts for when cash flows occur by finding the rate that makes the time adjusted NPV zero.
MIRR (Modified IRR) MIRR corrects IRR's reinvestment assumption by using a realistic reinvestment rate for positive cash flows and a finance rate for negative cash flows. MIRR produces a single rate even for non conventional cash flows.
Use Custom Fields and formula fields to capture cash flows and display IRR calculations on project Dashboards.
Model Project Returns in ClickUp

Common Questions About Internal Rate of Return (IRR)

What is internal rate of return?
IRR is the discount rate at which a project's net present value equals zero. It represents the effective annual return on invested capital. If a project's IRR is 15%, its returns discounted at 15% exactly equal its costs. Higher IRR means the project generates a higher return.
How do I calculate IRR?
IRR cannot be solved algebraically for most real projects. Use the IRR function in Excel or Google Sheets, which iteratively finds the discount rate that makes NPV equal zero. Input the initial investment as a negative number followed by each period's net cash flow.
When should I use IRR vs NPV?
Use IRR for go/no go decisions on individual projects (does the return exceed our hurdle rate?). Use NPV for comparing mutually exclusive projects (which one creates the most value?). IRR can produce misleading rankings when projects differ in size, duration, or cash flow patterns.
What is a hurdle rate?
A hurdle rate is the minimum acceptable return an organization requires from a project. It is typically set at the weighted average cost of capital (WACC) or slightly above it to account for project risk. Projects with IRR above the hurdle rate are generally accepted.